It would be good to get some guidance about where to put NIRS sensors for different sports for priority muscle andfor non-priority muscle. For some sports (rowing, x-c skiing, climbing) non-priority is especially tricky since most of the body is involved.

Have started using pectoralia major instead of deltoid as the less involved, non priority muscle during cycling, as - at least for me - it is less affected by handle bar (and hands-free) position changes. That said, the rate of desaturation under load is slower as well (which might have other benefits or issues), and I haven’t checked yet whether the less-noise is really advantageous relative to the size of “meaningful” changes.

Wondering if anyone else has tried the pectoralis major and would have some thoughts on this?

The concept of "uninvolved" muscle is somewhat misleading. When you are biking up an incline at full tilt, your upper body is certainly using resources. My "conjecture" is that looking at the result of cardiac output redistribution under locomotor muscle load, may provide real time physiologic insight into how best to race pace without premature decompensation. The costal area, being an involved muscle in breathing (especially at high intensity) may be an even better index, since sustained hypoxia would presumably harm the respiratory function (and therefore reduce gas exchange efficiency).

But, this is not proven (what else is new).

More importantly, it is tricky to get the sensor placement just right. I use a BSX and some micro adjustment of a few mm can make a difference. This could be related to the irregular surface of the rib cage, so an air gap will cause poor readings. The shape of the moxy could be more problematic. Studies have been done on the accessory muscles in the neck as well but this is not going to work in the field.

On a practical basis, once you get this to work, it seems like a potentially valuable parameter to follow as you are riding hard, as well as recovering.

Some preliminary tests show that the area just lateral to the nipple on the anterior chest may give similar data/readings as a costal/rib placement. This location should be readable with the Moxy if anyone would like to try it.

This is not a non involved muscle per se, it's just not involved with leg propulsion. You should see significant change as the respiratory muscles start competing with the locomotor system.

Insert Photos

Web address (URL)

Image URL

If your URL is correct, you'll see an image preview here. Large images may take a few minutes to appear.
Remember: Using others' images on the web without their permission may be bad manners, or worse, copyright infringement.